There is a scanning exposure apparatus for projecting part of a master pattern onto a substrate via a projection optical system, and scanning the master and substrate perpendicularly to the optical axis of the projection optical system, thereby transferring the master pattern to the substrate. This scanning exposure apparatus adopts a method of correcting target positions for all the axes of a substrate stage for holding a substrate or those of a master stage for holding a master in accordance with a polynomial whose variable is the position, along the scan axis, of the substrate or master stage in a coordinate system defined using the center of an exposure shot on the substrate or the center of the master pattern as an origin.
With micropatterning of semiconductor integrated circuits, an insufficient overlay (alignment) accuracy within a shot is becoming typical when different types of exposure apparatuses are used in mix-and-match. That is, only the function of faithfully transferring a master pattern onto a substrate is not satisfactory. Demands are arising for deforming a master pattern in accordance with the distortion within a shot on a layer already formed on a substrate and transferring the master pattern onto the substrate.
In recent years, a pellicle is generally attached to a master in order to prevent a projected image from being deteriorated by contamination of a master. However, adding a pellicle to a master mechanically distorts the master, which distorts the master pattern. An overlay error by the distortion of a master pattern is also increasing to a non-negligible degree.
However, the conventional method cannot cope with changes in combinations of exposure apparatuses or the distortion of a master pattern because the target position of the master or substrate stage is corrected in accordance with a fixed polynomial. The conventional method, therefore, suffers from a low overlay accuracy.